TWI421373B - Tungsten coating method for metal base material - Google Patents

Description

Tungsten coating method for metal base material Field of invention

The present invention relates to a method for coating a tungsten metal coating of a metal base material, and more particularly to a plasma-resistant and heat-resistant cracking resistance of an aluminum base material which can be used as a vacuum chamber or an electrode auxiliary material used in a semiconductor and TFT-LCD manufacturing process. (Heat and crack resistance), a tungsten coating method for a metal base material which is corrosion-resistant, thereby prolonging the service life of the vacuum chamber and reducing the degree of contamination.

Background of the invention

In the manufacture of a semiconductor or a TFT-LCD, an etching and vapor deposition gas is supplied by an electrode in a vacuum chamber, and electric power is applied to the gas to be activated into a plasma state, thereby performing etching or chemical vapor deposition of the substance on the substrate by high temperature. operating.

By these steps, an aluminum (Al) auxiliary material constituting a vacuum chamber or an electrode is exposed to a corrosive plasma gas at a high temperature. As a result, aluminum auxiliary materials may crack or corrode, which will cause particulate contamination from aluminum auxiliary materials, which will not only affect the service life of aluminum auxiliary materials, but also bring the adverse effects to the upcoming evaporation. Semiconductor or TFT-LCD substrates, etc., cause damage to the product or cause intermediate processing.

In order to solve the above problems, various techniques for resisting plasma resistance and thermal cracking resistance in a harsh environment in a vacuum chamber have been proposed in order to carry out a process on the surface of an aluminum auxiliary material.

U.S. Patent No. 5,641,375 discloses the reduction of plasma corrosion. And the wear of the wall and the anodization process of the aluminum vacuum chamber wall to form an anodized coating film. However, in the case of anodizing, although the plasma-resistant or heat-resistant cracking property is ensured to some extent by adjusting the thickness of the coating film at a high temperature, other problems such as serious damage of the coating film due to corrosion of the plasma gas occur.

A technique for forming an anticorrosive film of Al ₂ O ₃ , AlC, TiN, TiC, and AlN on an aluminum material is disclosed in Japanese Laid-Open Patent Publication No. 62-103379. However, although the above-mentioned anticorrosive film can improve plasma resistance, there is a problem that cracking occurs due to adhesion to aluminum.

Further, a coating method of performing a chromium oxide (Cr ₂ O ₃ ) coating film on the surface of an aluminum auxiliary material has been disclosed, but there is a limit to improving the corrosion resistance only by the chromium oxide coating film.

In the Korean Patent Publication No. 2000-59295, it is disclosed that a tungsten alloy coating is applied to a metal surface by electroplating to improve surface hardness and corrosion resistance, which is disclosed in the Republic of Korea Patent Publication No. 2004-272. A method of applying tungsten, palladium, nickel, and phosphorus to an aluminum alloy surface by a gold plating method.

These can ensure the plasma resistance of aluminum auxiliary materials to a certain extent by tungsten gold plating. However, even if tungsten gold plating is performed on the aluminum auxiliary material, the thermal expansion characteristics between the aluminum auxiliary material and the tungsten gold plating layer are largely different due to the high process temperature itself, and the resulting crack, peeling, foaming, etc. may cause New problems in the vacuum chamber aluminum materials prepared by the previous coating technology induced rapid particle contamination.

It is disclosed in the Republic of Korea Invention Patent Publication No. 2005-22184. The surface of the metal module of the semiconductor component is sequentially provided with a first nickel gold plating layer / a second nickel gold plating layer / a tungsten gold plating layer / a third nickel gold plating layer / a gold plating layer to extend the life of the equipment. According to this technique, the corrosion resistance of the metal module and the peeling between the metal layers can be released. However, it is necessary to form a five-layer film, which causes problems such as complicated processes and increased manufacturing costs.

Summary of invention

In order to solve the above problems, the present invention provides a plasma chamber, an aluminum alloy auxiliary material for use in a semiconductor and a TFT-LCD manufacturing process, which is resistant to plasma, heat cracking, and corrosion resistance, thereby extending the vacuum chamber. A tungsten coating method for a metal base material having a service life and a reduced degree of contamination.

Another object of the present invention is to provide a semiconductor and TFT-LCD part manufactured by the above method.

The present invention is achieved in the following manner. A first aspect of the invention relates to a tungsten coating method for a metal base material, comprising the steps of: performing an anodizing process on a metal base material comprising aluminum or an aluminum alloy to form an anodized coating film; and the above metal base material a step of forming an tungsten gold plating film by performing an electrolysis or electroless gold plating process on the anodized coating film; and a heat treatment stage; wherein the tungsten electrolytic gold plating is performed by preparing Na ₂ OWO ₃ . H ₂ O (5~50g/l), Na ₂ CO ₃ (10~30g/l), NH ₄ OH (1~15g/l), CH ₂ OHCOONa (1~5g/l), and Na ₃ C ₆ After an aqueous solution of H ₅ O ₇ (20 to 50 g/l) (pH 6 to 7), the temperature is adjusted to 75 to 85 ° C, and electric current is applied at a current density of 1 to 10 A/dm ² . Gold plating is prepared by including Na ₂ WO ₄ . 2H ₂ O (10~30g/l), NiCl ₂ . 6H ₂ O (5~15g/l), NaH ₂ PO ₂ . H ₂ O (10~30g/l), CH ₂ OHCOONa (5~15g/l), Na ₃ C ₆ H ₅ O ₇ (5~10g/l), CH ₄ N ₂ S (5~10g/l) After an aqueous solution (pH 8 to 10) of Na ₂ CO ₃ (10 to 25 g/l) and NH ₄ NF ₂ (5 to 15%), the temperature was adjusted to 80 to 90 ° C.

The anodizing step is carried out by applying a voltage of 0.1 to 100 V to a temperature of 25 to 100 ° C in an anodizing electrolyte of an acid selected from the group consisting of phosphoric acid, oxalic acid, sulfonic acid, and a combination thereof. 5 hours.

The heat treatment is carried out at a temperature of 350 to 600 ° C.

Further, the method further includes a step of forming a nickel gold plating film on the anodized film by an electrolytic gold plating process after the anodized film is formed.

The above nickel electrolytic gold plating is prepared by electrolytic nickel plating gold plating solution including NiSO ₄ . 6H ₂ O (100~500g/l), NiCl ₂ . After 6H ₂ O (20~80g/l) and H ₃ BO ₃ (20~50g/l) aqueous solution (pH 8~10), adjust the temperature to 40~80°C, 1~10A/dm ² The current density is applied by applying electric power.

According to a second aspect of the invention, a vacuum chamber component for semiconductor and TFT-LCD manufacturing is formed according to the method of the first aspect of the invention, and an aluminum oxide coating film or a tungsten gold plating film is sequentially formed on the surface.

Among them, a nickel gold plating film is formed between the aluminum oxide coating film and the tungsten gold plating film.

According to the invention, an anodized coating layer and a tungsten gold plating film are formed on the surface of the aluminum metal base material, thereby improving the plasma resistance and heat crack resistance of the metal. And corrosion resistance.

Detailed description of the preferred embodiment

The invention will now be described in greater detail with reference to the drawings. For a more vivid description, the results in each drawing are expanded. At this time, the same symbols in the drawings indicate the same structure. Also, when a layer is described as being "on" another layer, it can be understood that the above-described layer may be in direct contact with the other layers described above, or a third layer may be present between them.

First embodiment

Fig. 1 is a flow chart showing a method of coating a metal base material with a tungsten coating according to a first embodiment of the present invention, and Figs. 2 to 4 are views of the same.

First, a metal base material (11) made of aluminum or aluminum alloy is prepared (Fig. 2).

The metal base material (11) is subjected to a pretreatment process including a degreasing step, a water washing step, an etching step, and an electrolytic degreasing step.

In order to facilitate the formation of a coating film in the metal base material (11), the metal base material (11) is placed in a degreasing liquid at 60 to 80 ° C for degreasing step (Cleaning, Degreeing) in the pretreatment step. A water washing step is performed to remove the above-mentioned degreasing liquid and impurities. Then, an etching process is performed to increase the surface area, and then an electrolytic degreasing process (electrocleaning) is performed. In this pretreatment step, in addition to the above steps, a pretreatment process such as applying ultrasonic waves may be added or replaced.

Then, the surface of the metal base material (11) is anodized to form an anodized coating film (13) having pores on the surface of the metal base material (11) (Fig. 3).

Specifically, the metal base material (11) is used as a positive electrode, and the metal base material (11) is immersed in an anodic acid electrolyte including an acid, and a voltage is applied to cause anodization. At this time, the metal base material (11) is electrically oxidized from the surface by the applied voltage, and the surface of the above metal base material (11) is converted into an aluminum oxide film (Al ₂ O ₃ ) as an anodized coating film (13). Then, a continuous voltage is applied to form a vertical anodic oxide coating film (13) with respect to the metal base material (11).

At this time, the anodic oxidation electrolyte for oxidation includes an acid selected from the group consisting of phosphoric acid, oxalic acid, sulfonic acid, and a combination thereof, and the dilute solution is preferably 15 to 18% by weight of sulfonic acid or 1 to 5 wt% aqueous oxalic acid solution.

At this time, the anodic oxidation is performed by applying a voltage of 0.1 to 100 V, and the temperature is 25 to 100 ° C for 0.5 to 5 hours, and those skilled in the art can consider the type of the acid, the diameter of the nanopore and the high order (highly Various factors such as ordered pores are used for various deformations.

This anodization needs to be carried out more than once, and if necessary, it can be carried out 2 to 4 times, thereby improving the order of the pores.

The anodized coating film (13) having a plurality of pores thus formed is not a completely crystalline coating film, but forms an amorphous Al ₂ O ₃ coating film. The anodized coating film (13) exhibits ceramic properties by 50% growth toward the metal wood (11) side and 50% growth to the outside, but has no cracking property with the metal base material (11). In the case of a completely crystalline coating film (that is, an Al ₂ O ₃ coating film formed by spraying on an Al base material), since it is completely ceramic crystal, it exhibits 4 times thermal expansion characteristics as compared with the Al base material. .

A washing step is performed to increase the efficiency of the subsequent coating step after the anodization. Since such a process requires high precision, a thorough water washing process must be performed between the process and the process.

Then, an electrolysis or electroless plating process is performed on the above oxide coating film (13) to form a tungsten gold plating film (15) (Fig. 4).

Tungsten has excellent corrosion resistance, plasma resistance and heat crack resistance, so that the physical properties of the metal base material (11) can be improved.

In particular, in the present invention, a tungsten gold plating film (15) is formed on the porous anodized coating film (13). At this time, as shown in Fig. 3, tungsten is present inside the pores of the anodized coating film (13). The upper part is coated with tungsten. Thereby, the adhesion between the metal base material (11) and the tungsten gold plating film (15) is improved, and the tungsten gold plating film (15) is formed, which maximizes the effect.

The tungsten gold plating film (15) is formed by an electrolysis and tungsten electrolytic coating process.

First, the electrolytic gold plating process is carried out by preparing Na ₂ OWO ₃ as an electrolytic tungsten coating liquid. H ₂ O (5~50g/l), Na ₂ CO ₃ (10~30g/l), NH ₄ OH (1~15g/l), CH ₂ OHCOONa (1~5g/l), and Na ₃ C ₆ After an aqueous solution (pH 6 to 7) of H ₅ O ₇ (20 to 50 g/l), the temperature was adjusted to 75 to 85 ° C, and electric power was applied at a current density of 1 to 10 A/dm ² .

Moreover, the electroless gold plating process comprises preparing Na ₂ WO ₄ as an electroless tungsten coating liquid. 2H ₂ O (10~30g/l), NiCl ₂ . 6H ₂ O (5~15g/l), NaH ₂ PO ₂ . H ₂ O (10~30g/l), CH ₂ OHCOONa (5~15g/l), Na ₃ C ₆ H ₅ O ₇ (5~10g/l), CH ₄ N ₂ S (5~10g/l) After an aqueous solution (pH 8 to 10) of Na ₂ CO ₃ (10 to 25 g/l) and NH ₄ NF ₂ (5 to 15%), the temperature was adjusted to 80 to 90 ° C.

At this time, the electrolysis and the electroless gold plating process are performed in a time period in which the tungsten gold plating film (15) has a thickness of 5 to 50 μm. If the thickness of the tungsten gold plating film (15) is less than 5 μm, the problem of severely resisting plasma characteristics may be caused. If the thickness of the tungsten gold plating film (15) exceeds 50 μm, the bubble problem of the above-mentioned prior tungsten gold plating film may occur. And the problem of interface peeling, so as to maintain the above range.

After the tungsten gold plating film (15) is formed, a water washing step and a drying step are performed.

Then, the above metal base material is subjected to heat treatment to complete the process.

The above heat treatment is carried out under redox conditions of 350 to 600 ° C. By this heat treatment, the effect of increasing the density of the film of the tungsten gold plating film (15) and improving the adhesion of the anodized film (13) is obtained. If the heat treatment temperature is less than 350 ° C, the mechanical properties of the tungsten coating film are lowered. On the contrary, if the temperature exceeds 600 ° C, the base material is damaged and the anodized coating film is cracked, and the like, and the above range is maintained.

As described above, in the present invention, an anodized coating film (13) having a porous structure is formed on the surface of the metal base material (11) by anodization to ensure plasma resistance and heat crack resistance, and a tungsten gold plating film is formed on the upper portion thereof (15). Further, it has corrosion resistance, and tungsten is present inside the pores of the anodic oxide coating film (13) having a porous structure, thereby having the effect of releasing the peeling between the anodized coating film (13) and the tungsten gold plating film (15).

When a coating of a metal layer such as tungsten is applied to the prior metal base material (11), since the adhesion between the metal base material (11) and the metal layer is low, zincate is required to improve adhesion ( In the Zincate treatment, an adhesion layer is additionally provided between the metal base material (11) and the metal layer, and in the present invention, it is not necessary to carry out these steps, which has the effect of simplifying the process and reducing the manufacturing cost.

Furthermore, the present invention further includes a step of forming a nickel gold plating film on the anodized film by an electrolytic gold plating process after the anodized film is formed.

The nickel gold plating film is disposed between the anodized coating film and the tungsten gold plating film to improve the adhesion to the interface and improve the adhesion between the anodized coating film and the tungsten gold plating film.

Second embodiment

Fig. 5 is a flow chart showing a method of coating a metal base material with a tungsten coating according to a second embodiment of the present invention, and Figs. 6 to 7 are views of the same.

Specifically, the surface of the metal base material is anodized to form an oxide coating film.

The details of the anodization in this case can be referred to in the first embodiment.

Then, a nickel gold plating film (17) is formed on the metal base material (11) forming the anodized coating film (13) by electrolytic gold plating (refer to Fig. 7).

The above electroplating gold plating process is performed by electrolytic nickel plating gold plating solution including NiSO ₄ . 6H ₂ O (100~500g/l), NiCl ₂ . After 6H ₂ O (20~80g/l) and H ₃ BO ₃ (20~50g/l) aqueous solution (pH 8~10), adjust the temperature to 40~80°C, 1~20A/dm ² The current density is applied by applying electric power.

At this time, as shown in Fig. 6, the nickel gold plating film (17) has nickel inside the pores of the anodized coating film (13) and nickel on the upper portion thereof. As a result, the adhesion between the metal base material (11) and the nickel gold plating film (17) is improved, and a subsequent tungsten gold plating film (19) is formed on the upper portion thereof.

Then, a tungsten gold plating film (19) is formed by performing electrolysis or electroless gold plating on the nickel gold plating film (17) (see Fig. 7).

The tungsten gold plating film (19) is carried out by electrolysis or electroless process, and the detailed steps are described in the first embodiment.

Next, the metal base material is subjected to heat treatment to complete the process.

At this time, the tungsten gold plating film (19) is formed before the heat treatment, and then a drying step is performed.

Through the above stages, an anodized coating film/tungsten gold plating film or an anodized coating film/nickel gold plating film/tungsten gold plating film is sequentially formed on the surface of the metal base material of the present invention.

The surface process of the metal base material according to the present invention is used for surface treatment of various auxiliary materials such as a heater and a shower head (air diffuser) used in a vacuum chamber and a vacuum chamber of a semiconductor and a TFT-LCD manufacturing apparatus.

The main material of the above-mentioned auxiliary material is aluminum or an aluminum alloy, and tungsten is coated on the surface of the auxiliary material to have an effect of improving corrosion resistance, plasma resistance and heat crack resistance. As described above, according to the method of the present invention, the physical properties can be maximized, the adhesion between the tungsten gold plating film and the auxiliary material can be improved, and the process is simple and the effect is superior and the cost can be reduced as compared with the previous surface treatment process. The advantages.

For a better understanding of the invention, the preferred embodiments are disclosed below. However, the following examples are provided for easier understanding of the present invention, and the contents of the present invention are not limited to the contents of the examples.

Example 1

The aluminum substrate is subjected to degreasing, water washing, etching, and electrolytic degreasing by a prior method to carry out a pretreatment process.

Then, the aluminum substrate subjected to the pretreatment step was immersed in an acid solution having a concentration of 0.5 M in a weight ratio of sulfonic acid and oxalic acid of 1:5, and then used as an anode to supply a current of 0.2 A/cm ² at 28 ° C. Minutes to form an anodized coating film.

The aluminum substrate was washed with DI water and immersed in an electroless gold plating bath for forming a tungsten gold plating film (Na ₂ WO ₄ .2H ₂ O (30 g/l), NiCl ₂ .6H ₂ O (5 g/l), NaH. ₂ PO ₂ .H ₂ O (12 g/l), CH ₂ OHCOONa (5.5 g/l), Na ₃ C ₆ H ₅ O ₇ (10 g/l), CH ₄ N ₂ S (5 g/l), Na ₂ In CO ₃ (15 g/l) and NH ₄ NF ₂ (12%), the mixture was stirred and precipitated at pH 10 and 90 ° C for 30 minutes. A tungsten-plated gold film having a thickness of 25 μm was formed on the anodized film by this electroless method.

Then, after washing with water, it was dried at normal temperature for 1 hour, and then heat-treated at 400 ° C for 2 hours in an oxygen atmosphere.

Example 2

The aluminum substrate is subjected to degreasing, water washing, etching, and electrolytic degreasing by a prior method to carry out a pretreatment process.

Then, the aluminum substrate subjected to the pretreatment step was immersed in an acid solution having a concentration of 0.5 M in a weight ratio of sulfonic acid and oxalic acid of 1:5, and then used as an anode to supply a current of 0.2 A/cm ² at 28 ° C. Minutes to form an anodized coating film.

The aluminum substrate was washed with DI water and immersed in an electrolytic cell for forming a tungsten gold plating film (Na ₂ OWO ₃ .H ₂ O (20 g/l), Na ₂ CO ₃ (10 g/l), NH ₄ OH (5 g). /l), CH ₂ OHCOONa (1 g/l), and Na ₃ C ₆ H ₅ O ₇ (15 g/l)), and then supplied a 5 A current for 40 minutes. A tungsten-plated gold film having a thickness of 25 μm was formed on the anodized film by this electrolytic method.

Then, after washing with water, it is dried at room temperature for 1 hour and then in oxygen. Heat treatment at 400 ° C for 2 hours under the environment.

Example 3

The aluminum substrate is subjected to degreasing, water washing, etching, and electrolytic degreasing by a prior method to carry out a pretreatment process.

Then, the aluminum substrate subjected to the pretreatment step was immersed in an acid solution having a concentration of 0.5 M in a weight ratio of sulfonic acid and oxalic acid of 1:5, and then used as an anode to supply a current of 0.2 A/cm ² at 28 ° C. Minutes to form an anodized coating film.

The aluminum substrate was washed with water and immersed in an electrolytic cell for forming a nickel gold plating film (NiSO ₄ .6H ₂ O (400 g/l), NiCl ₂ .6H ₂ O (20 g/l), H ₃ BO ₃ (30 g/l). )), and then a current of 20 A was supplied for 10 minutes to form a nickel-plated gold film having a thickness of 5 μm on the anodized film.

Then, after careful washing with DI water again with the cell above the aluminum plate was immersed _{(Na 2 OWO 3 .H 2 O} (20g / l), Na 2 CO 3 (10g / l), NH 4 plated film formed on the tungsten OH (5 g/l), CH ₂ OHCOONa (1 g/l), and Na ₃ C ₆ H ₅ O ₇ (15 g/l)), and then supplied a 5 A current for 40 minutes to form a tungsten gold-plated film having a thickness of 30 μm.

Thereafter, it was dried at 4 ° C for 4 hours, and then heat-treated at 400 ° C for 4 hours in an oxygen atmosphere.

Comparative example 1

The aluminum substrate is subjected to degreasing, water washing, etching, and electrolytic degreasing by a prior method to carry out a pretreatment process.

The aluminum substrate was washed with water and immersed in an electrolytic cell for forming a nickel gold plating film (NiSO ₄ .6H ₂ O (400 g/l), NiCl ₂ .6H ₂ O (20 g/l), H ₃ BO ₃ (30 g/l). )), and then a current of 20 A was supplied for 10 minutes to form a nickel-plated gold film having a thickness of 5 μm on the anodized film.

Comparative example 2

The aluminum substrate is subjected to degreasing, water washing, etching, and electrolytic degreasing by a prior method to carry out a pretreatment process.

Then, the aluminum substrate subjected to the pretreatment step was immersed in an acid solution having a concentration of 0.5 M in a weight ratio of sulfonic acid and oxalic acid of 1:5, and then used as an anode to supply a current of 0.2 A/cm ² at 28 ° C. Minutes to form an anodized coating film.

Test example 1

In order to confirm whether or not the tungsten gold plating film was formed on the above substrate by the above-described Example 1, the surface components were analyzed by a scanning electron microscope (SEM) and EDAX, and the results are shown in Fig. 8.

Fig. 8 shows the absorption spectrum of the surface component of the tungsten gold plating film of Example 1.

Referring to Fig. 8, it is understood that 30% of tungsten (W) is formed on the anodized film.

Fig. 9 is a front view showing a tungsten gold plating film produced in Example 1, and Fig. 10 is a side view showing an anodized coating film/tungsten gold plating film laminated on the substrate in Example 1. Referring to Figures 9 and 10 above, it was found that an anodized film (Anodizing film) was formed on the Al base material, and a tungsten gold plating film was formed thereon.

Test Example 2: Determination of corrosion resistance

In order to measure the corrosion resistance of the substrates produced in the above Examples 1 to 3 and Comparative Example 1 and Comparative Example 2, the substrate was immersed in a HCl 10% solution (25). The degree of corrosion over time was measured after ° C), and the measurement results are shown in Fig. 8.

Fig. 11 is a graph showing the degree of corrosion of the substrate in Examples 1 to 3 and Comparative Example 1 and Comparative Example 2. Referring to Fig. 11, it is understood that the degree of corrosion of the coating film in the case of the substrates of Examples 1 to 3 is low.

Test Example 3: Resistance to plasma determination

In order to measure the plasma resistance of the substrates produced in the above Examples 1 to 3 and Comparative Examples 1 and 2, the substrate was placed in a PECVD chamber, and plasma was generated by NF ₃ gas at 380 ° C to determine the system. There is no surface damage, and the results are shown in Table 1.

Test Example 4: Determination of heat crack resistance

In order to measure the heat-resistant cracking property of the substrates produced in the above Examples 1 to 3, the process of heating at 500 ° C for 10 times and cooling by water at normal temperature was repeated 10 times, and then the surface of the substrate was measured by a scanning electron microscope.

Fig. 12 is a scanning electron microscope photograph showing the tungsten gold plating film of Example 1, and Fig. 13 is a scanning electron microscope showing the nickel gold plating film of Comparative Example 1. Photograph, Fig. 14 shows a scanning electron microscope photograph of the anodized film of Comparative Example 2.

Referring to Fig. 12, it is understood that the tungsten gold plating film produced by the present invention does not crack. In contrast, it was confirmed that cracks occurred in the case where a nickel gold plating film or an anodized film was simply formed on the substrate in FIGS. 13 and 14.

Industrial availability

The surface process agent for a metal base material according to the present invention is used for surface treatment of various auxiliary materials such as a heater and a shower head (air diffuser) used in a vacuum chamber and a vacuum chamber of a semiconductor and a TFT-LCD manufacturing apparatus.

11‧‧‧Metal base metal

13‧‧‧Anodized film

15, 19‧‧‧ tungsten gold plating film

17‧‧‧Formed nickel-plated gold film

Fig. 1 is a flow chart showing a method of coating a metal base material with a tungsten coating according to a first embodiment of the present invention, and Figs. 2 to 4 are views of the same.

Fig. 5 is a flow chart showing a method of coating a metal base material with a tungsten coating according to a second embodiment of the present invention, and Figs. 6 to 7 are views of the same.

Fig. 8(a) shows the absorption spectrum of the surface component of the tungsten gold plating film of Example 1.

Fig. 9 is a front view showing a tungsten gold plated film produced in Example 1.

Fig. 10 is a side view showing an anodized coating film/tungsten gold plating film laminated on a substrate in Example 1.

Fig. 11 is a graph showing the corrosion degree of the substrate in Examples 1 to 3 and Comparative Example 1 and Comparative Example 2 over time.

Fig. 12 is a scanning electron micrograph showing the tungsten gold plating film of Example 1.

Figure 13 is a scanning electron microscope showing the nickel-plated gold film of Comparative Example 1. photo.

Fig. 14 is a scanning electron micrograph showing the anodized film of Comparative Example 2.

Claims (5)

A tungsten coating method for a metal base material, comprising the steps of: performing an anodizing process on a metal base material comprising aluminum or an aluminum alloy to form an anodized coating film; and performing electrolysis on the anodized coating film of the metal base material Or a stage of forming a tungsten gold plating film by an electroless gold plating process; and a heat treatment stage; wherein the tungsten electrolytic gold plating is prepared by including Na ₂ OWO ₃ . H ₂ O (5~50g/l), Na ₂ CO ₃ (10~30g/l), NH ₄ OH (1~15g/l), CH ₂ OHCOONa (1~5g/l), and Na ₂ C ₆ After an aqueous solution of H ₅ O ₇ (20 to 50 g/l) (pH 6 to 7), the temperature is adjusted to 75 to 85 ° C, and electric current is applied at a current density of 1 to 10 A/dm ² . Gold plating is prepared by including Na ₂ WO ₄ . 2H ₂ O (10~30g/l), NiCl ₂ . 6H ₂ O (5~15g/l), NaH ₂ PO ₂ . H ₂ O (10~30g/l), CH ₂ OHCOONa (5~15g/l), Na ₃ C ₆ H ₅ O ₇ (5~10g/l), CH ₄ N ₂ S (5~10g/l) After an aqueous solution (pH 8 to 10) of Na ₂ CO ₃ (10 to 25 g/l) and NH ₄ NF ₂ (5 to 15%), the temperature was adjusted to 80 to 90 ° C. A method for coating a tungsten metal coating of a metal base material according to claim 1, wherein the anodizing step is an anode of an acid selected from the group consisting of phosphoric acid, oxalic acid, sulfonic acid, and combinations thereof. In the oxidizing electrolyte, a voltage of 0.1 to 100 V is applied, and the temperature is carried out at a temperature of 25 to 100 ° C for 0.5 to 5 hours. Tungsten coating of a metal base material according to claim 1 of the patent application scope The method wherein the heat treatment is performed at a temperature of 350 to 600 ° C. A method for coating a tungsten metal coating of a metal base material according to claim 1, further comprising the step of forming a nickel gold plating film on the anodized coating film by an electrolytic gold plating process after forming the anodized coating film. According to the tungsten coating method of a metal base material according to claim 4, the nickel electroplating is performed by using an electrolytic nickel plating solution to prepare NiSO ₄ . 6H ₂ O (100~500g/l), NiCl ₂ . After 6H ₂ O (20~80g/l) and H ₃ BO ₃ (20~50g/l) aqueous solution (pH 8~10), adjust the temperature to 40~80°C, 1~10A/dm ² The current density is applied by applying electric power.